Prevalence of Mastitis Pathogens in France: Antimicrobial Susceptibility of Staphylococcus aureus, Streptococcus uberis and Escherichia coli

The prevalence of bovine mastitis in France was established using 11 publications covering the period 1995- 2012. The papers involved epidemiological surveys or treatment trials. Bacteriological analyses were performed on 777, 923 and 2341 aseptically collected quarter milk from acute, clinical and subclinical mastitis respectively. Escherichia coli and Streptococcus uberis were the most prevalent pathogens in acute and clinical mastitis whereas Staphylococcus aureus and coagulase negative staphylococci were the most frequently isolated pathogens in subclinical mastitis. The prevalence of Corynebacterium bovis and Streptococcus agalactiae was low whatever the severity of mastitis. The epidemiological data could be useful in the choice of treatment and provide indicators for future research with a view to developing new efficient vaccines. The susceptibility of 240 isolates (80 Streptococcus uberis, 80 Staphylococcus aureus, 80 Escherichia coli) isolated in 2013 from aseptically collected quarter milk from clinical and subclinical mastitis to 12 antimicrobial agents was determined by measuring their minimal inhibitory concentrations. Overall resistance levels were very low except for S. aureus towards penicillin G (21.3%) and for Str. uberis towards tylosin and cloxacillin (respectively 13.8% and 32.5%).